Indoor spaces such as offices, hospitals, retail stores, educational institutions and the like have two main issues: (1) maintaining proper air quality and air movement; and (2) providing adequate lighting. Indoor spaces often have only a single HVAC system that provides air and heat to all of the different sized offices or rooms within a space. Separately, the indoor space utilizes a series of LED lights that are mounted in ceiling tiles having a dimension of 2 ft.×2 ft. or 2 ft.×4 ft. There is a need for a system which can move air within an indoor space which supplements the primary HVAC system while at the same time providing ample lighting within the indoor space while fitting into the dimensions of a ceiling tile. The system also can provide a cooling effect on the LED lights to prolong the life-span of the lights.
According to the U.S. Department of Energy (DOE), more than 360 million troffers provide general lighting in commercial building interiors. With their standard dimensions of 2 ft.×4 ft., 1 ft.×4 ft. and 2 ft.×2 ft., these luminaires are popular in dropped, acoustical-tile ceilings with a low ceiling height (less than or equal to 9 feet). The installed troffer base is predominantly linear fluorescent. In recent years, the development of LED technology has resulted in a broad selection of products designed to challenge fluorescent, offering up to 70 percent energy savings, longer life and controllability.
There does exist a problem with LED lights. Excessive heat causes damage to LED lights. LED bulbs that produce white light typically generate excessive heat that must be conducted away from the LED light system. Proper thermal management is critical to maintaining the original brightness and extending the lifespan of LED lights. Unfortunately, due to component costs, many manufacturers do not include the materials or structures necessary to provide proper heat transfer, thereby reducing the performance of the product. For example, most LED lighting manufacturers use less expensive and less reliable circuit boards that do not transfer heat well. Heat build-up in LED lights will damage the material, decrease the effectiveness of the light and decrease the lifespan of the lighting unit.
The secret to extending the useful life of an LED fixture is proper thermal management. There are several factors that affect the thermal performance of any fixture including the ambient air temperature, but LEDs specifically suffer from improper thermal design. The displacement of waste heat produced by LED lights is paramount to the longevity of the LED lights and can provide an advantage to a company in the emerging LED lighting industry.
The energy consumed by an incandescent bulb produces around 12% heat, 83% infrared radiation and only 5% visible light. A typical LED light produces 15% visible light and 85% heat. It is important to dissipate heat from LED's through efficient thermal management. The operating temperature of an LED light affects the lifespan of the LED. LED lights do not tend to fail catastrophically, instead the lumen output of the LED decreases over time. Elevated internal temperatures of the LED cause accelerated deterioration of the LED lights.
One of the major complaints levied by people working in an office, school, hospital, or commercial space concerns the temperature in the space. Complaints about temperatures are not just a matter of employees' preferences and tolerances. Temperature has been found to have a direct correlation to productivity. It is believed that productivity is linked to the temperature of the building. In addition to temperature issues within a building, employees may experience headaches, dizziness, nausea, irritation, cough, fatigue, asthma and other symptoms due to what has been termed “sick building syndrome.” The primary sources of indoor air quality problems are believed to be inadequate ventilation and contamination from within the building.
Further, in an office or indoor environment, the absence of adequate ventilation causes irritating or harmful contaminants to accumulate, which causes worker discomfort, health problems and reduced performance levels. Such harmful contaminants include bacteria, fungus, mold or viruses that can cause people to become sick. There is a need for an air circulation mechanism which reduces airborne contaminants. Air purification is an important part of an HVAC system. A typical indoor HVAC system is not a substitute for source control or ventilation.
There is also a need to create what is called a virus or bacteria kill chamber. The kill chamber, or kill zone, must be self-enclosed such that any UV light source does not exit the kill chamber.
Moreover, it would be advantageous for an air circulation mechanism to fit within the footprint of a typical ceiling tile.